By further comparison, Australia's Donald Bradman, usually acknowledged as cricket's best batsman, retired aged 39 in 1948 with 6,996 Test runs, including 29 centuries, in 52 matches.

And despite Bradman's staggering Test average of 99.94, West Indian great Brian Lara said Tendulkar was not only the best of all time, but that his records could be unmatchable.

"No argument at all - Sachin Tendulkar, for me, has had the greatest cricket career of anyone who has ever played the game," Brian Lara said in London this week.

"His stats speak for themselves," added Lara. "I don't think there is any 16-year-old who is going to embark on the sort of career that Sachin Tendulkar has had and walk away from the game at 40 or 41 with such great achievements."

Among current players, Tendulkar's Test record could possibly be matched by just two batsmen -- the indefatigable all-rounder Kallis, and England captain Alastair Cook.

Kallis, 38, has scored 13,140 runs in 164 Tests at a commendable average of 55.44. Cook, 28, already has 7,801 runs from 97 Tests, with 25 centuries and an average of 47.85.

However, Dev said the growth of one-day and Twenty20 cricket -- and the rigorous physical demands of the modern game -- could put Tendulkar's statistics out of reach.

"One would need to play for 25 years to achieve those feats, but can modern-day players last that long?" he asked. "Most don't even play enough Test matches these days."

Tendulkar featured in just one Twenty20 international, preferring to leave the shortest version to younger players, but turned out for the Mumbai Indians in domestic T20 up until last month.

The proliferation of T20, as well as the money on offer, has seen many of the game's best batsmen limiting their appearances for their country, as well as a tightening of the international schedule.

The West Indies star batsman Chris Gayle, who should be in the opposition starting line-up for Tendulkar's farewell Test in Mumbai, has missed several tours for his country to turn out for T20 franchises instead.

Former India opener Sunil Gavaskar pinpointed prolific youngster Virat Kohli as someone who may surpass Tendulkar's tally of 49 one-day centuries, but said his Test record appeared impregnable.

Kohli, 25, has scored 4,919 runs in 113 one-day innings so far, with 17 hundreds. At the same stage, Tendulkar had hit 4,001 runs with only eight centuries.

"It will be well nigh impossible to play 200 Test matches or reach 51 Test hundreds, but the manner in which Virat is batting, 49 hundreds definitely look possible," Gavaskar told NDTV news channel.

"He may still be 32 tons away, but the number of one-dayers India play these days, he could do it."

"The thing with Sachin is that statistics don't lie," Muralitharan wrote in a recent column in the Times of India.

"He was consistent at home and overseas. He was comfortable against pace and spin. He could thrive on slow pitches and bouncy pitches."

Former South African opener Gary Kirsten, who played alongside Tendulkar and then coached him and India to World Cup glory in 2011, said his rigorous training and practice sessions before every match were the key.

"He always had a burning desire to score big in every innings," Kirsten told the Economic Times. "Whilst many might be willing to compromise a little after some success, Sachin would become more ruthless and prepare even harder for the next game.

"I really enjoyed watching his attention to detail during preparation time. The thing that means the most to me is his absolute love affair with the game of cricket.